clark



' 16,651 June 14 1927' G. H. CLARK Re ADJUSTMENT OF WAVE LENGTHS Original Filed Jan. 18, 1915 2 Sheets-Sheet l INVENTOR geo geH (277% 01%? if A TTORNEKY 16 651 June 1927' e. H. CLARK ADJUSTMENT OF WAVE LENGTHS Original Filed Jan. 18, 1915 2 Sheets-Sheet 2 V GeorgeHC'lark I #16 A TTOR/VEG Reissued June 14, 1927.

UNITED, STATES PATENT OFFICE.

GEORGE n.

ASSIGNMENTS, TO mnro WARE.

Original No. 1,328,155, dated November 25, 1919, Serial No. 2,799,1i1ed-Ianuary 18, 1915. Application for .CLARK, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR, BY YN IESNE CORPORATION OF AMERICA, A CORPORATION OF DELA- ADJ'USTMENT OF WA VE.LENGTHS.

reissue filed. April 20, 1920. Serial No. 375,381.

My invention relates to telegraphy, te-

lephony, or like systems in which the energy employed is in the electro-radiant form for space systems or inthe form of high frequency Oscillations for conductive systems.

Heretofore in the practical and commercial use of systems such as above referred to, it has been impossible with the prior art ap paratus available to change the transmission or reception quickly and promptly from a setting for one wave length or frequency to a setting for another wave length or frequency, because involving more than a single movement or adjustment of an apparatus, in fact involving a plurality of independent movements for tuning and adjusting operations with resulting loss of considerable time which is a serious disadvantage and a chief hindrance in the satisfactory operation of apparatus of this character.

It is one object of my invention to provide, either at the transmitting or receiving station, or both, apparatus whereby settings for different wave lengths or frequencies may be made bya single operation of switching mechanism which same time insure proper or desired coupling between inductively related oscillation circuits. A further object of my invention is to provide anarrangement transformers and loading inductance of maximum convenience and efiiciency.

To these ends I have 'devised the system and apparatus hereinafter described and constituting an embodiment of my invention.

For an illustration of one of the forms my invention may take reference is to be had to the accompanying drawings, in which:

Fig. 1 is a diagrammatic view illustrating a typical transmitting apparatus to which my invention may be applied.

Fig. 2 is a diagrammatic view illustrating electrical connections and co-operating switching mechanism for carrying out my invention in transmitting apparatus.

Fig. 3 is a diagrammatic view similar to Fig. 2 when used in receiving apparatus.

Fig. 1 shows a typical transmitting apparatus to which reference is made for an explanation of my invention.

Referring to this figure, G is an alternat shall at the of oscillation ofcurrent connected in circuit with the primary p of -a step-up transformer, the primary circuit being controlled by the usual transmitting 4 key 70. The high tension secondary s of'the step-up transformer has its terminals connected to either side of the spark gap 9 which may be of the simple type indicated or may be of the quenched gap type, or any other suitable type. The gap 9 is in circuit with the condenser or capacity K and thevariableportions of the primary P of the oscillation transformer, the circuit PKg being here shown as a closed oscillation circuit. The open or antenna circuit comprises a variable portion of the secondary S of the oscillation transformer, a variable por tion of the loading inductance L, beyond the inductive influence of the primary P, the antenna or aerial conductor A, and the earth connection. E, a radiation meter M,'such as a hot wire ammeter, being included for purposes ofconvenience.

When it is desired to transmit energy of a certaln frequency or wave length, the variable or sliding contact in the. primary circuit is moved to such point onthe primary P, as for example the point 1, which will insure the primary circuit producing oscillations of the desired frequency, corresponding with wave lengthNo. 1. This setting may be determined by a wave meter, by calculation, or otherwise. The open or antenna circuit is then attuned to this same frequency or wave length, when the coupling between P and S is loose, by adjusting the variable contacts on S or on L until the meter M. gives a maximum reading. Then by making the coupling between P and S closer and of such character as is to be employed in transmitting energy having wave length No. 1 the rider or contact sliding on the loading inductance L will have to be moved'to some new position until'the wave meter indicates but a single maximum in the resonance curve, and the adjustment is further varied until with this single maximum in the resonance curve the meter M indicates a maximum reading for ods the-setting of the inductance L, of secondary S and of primary P are determined ductance in the antenna or open circuit for.

for the wave length No. 1. Similarly for another wave length, say No. 2, the settings will be at the points indicated by 2; the settings for a third wave length b 3, and for the fourth wave length by 4.

In all cases the necessary or desired inany given wave length can be so proportioned between the secondary, S and the load- 1 ing inductance L that the same mechanical coupling, that is, same physical or mechanical distance or relation between the primary P and secondary S can be obtained for all wave lengths. of the relative amounts of inductance in S and L for any wave length, ifthe coupling is too close, the .number of turns in S is reduced and the number of turns in L is increased, and conversely if the coupling is too loose, the number of turns in L is reduced and the number of turns in S is increased.

B my invention I provide switching mec anism, a single movement of which Wlll transfer the movable contacts on P, S and L to the proper points for transmission ofthese various wave lengths while ma1nta1n-- ing the desired or proper coupling between the primary P and the secondary S, this coupling being generally such as will cause a transmission of maximum energy from the closed oscillation circuit to the open antenna circuit.

In Fig.- 2 this same general arrangement is shown except that the primary p of the step-up transformer and its circuit are om1tted,and there' is added the switching mechanism referred to and additional variable-inducta-n'ces or variometers in the open and closed circuits for sake of convenience.

The points 1, 2, 3 and 4 for the four different wave lengths are indicated as in Fig. 1. From the four points 1, 2, 3 and 4 of the primary P connections are made to the four contacts P P, P and P adapted to be engaged by the switch arm P Similarly the" four points 1, 2, 3 and 4 on the secondary S are connected respectively with the four switch contacts S S S? and S, with which the movable switch arm S is adapted to engage. And similarly the four points 1, 2, 3

and 4 on the inductance L are connected with i the four switch contacts L, L, L and L with which the switch arm L is adapted to en a e. Inductance L is here shown as di- -vi' ed into two arts,though a reater num-' ber may be emp oyed if desired, 1n order that when one part of the inductance is not in use it may e cut out of circuit- (or short circuited as hereinafter described), to prevent ener consumption by such idle ortion.

.For t is purpose connections are ma e' from the adjacent ends of the two inductance ortions by conductors a and b with the sw1tch contacts and d which are adapted to be b i g an both arts oi thamductance In making this adjustment length. When shifting are to be used, by the switch contact e. The

antenna A is connected with the switch arm L. And the switch arms S connectsto. the earth E through the radiation meter M and, if desired, an additional variable inductance L, which may be set at once for all wave lengths of a group, may be employed.

And in the primary circuit an additional inductance L may be employed ifrequired or desired. 4

The switch arms P, S, L and e are mechanically connected together, as by member or shaft 7", which may be provided with a hand wheel or other operating device h.

In this figure are shown two condensers or banks of condensers K, K which may be connected in parallel or in series with each other connected together but insulated from each other and mechanically connected with the operating mechanism for the switches previously described, this connection causing the contacts 1* and t to be in position shown, and thereby connect the condensers K, K in parallel with each other, for the three right hand positions of the switch P, but when the switch P engages with the contact P, the contacts 25, 1' are shifted toward the left, 1' remaining in contact with j and engaging the blank g, while if remains in contact with n and connects the same to 0, in which case the condensers K, K are in series with each other in the'primary circuit, the switch P being connected with the contact m. The object of this is to have less capacity in circuit for the shorter wave length or lengths so that the corresponding co-operating in'ductance ofthe primary circuit will be a substantial part of the primary P. And in reverse movement of the switch arm P, the

switch contacts 6 and 1" are restored to the po-- sition shown and occupy such position for all ositions of the switch arm P when en: gaging contacts P P and P.

With the parts in the positionnllustra'ted in Fig. 2 the connections are such as to transmit wave length No. 3, the amount of inductance L, the coupling between P and S, the number of turns or length of P' in the primary circuit being proper for this wave to any of the other positions the other an corres onding'wave lengths will be transmitted w 'le maintaining the coupling at the proper and desired amount and the amount of inductance in the closed and open circuits at the proper amount. 7

When the switch arm L moves to the left on to contact L or contact L the upper partof the induetanceL will not be in use, and it s therefore open circuited, for both switching apparatus,

- generally termed,

these positions by the withdrawal of the switch contact 0 from bridging relation with contacts 0 and i While the apparatus thus far described has been transmitting apparatus it will be understoodthat the same functions may be procured for receiving apparatus.

Thus in Fig. 3, Fig. 2 has been reproduced, but in place of the apparatus shown in the primary circuit of Fig. 2, receiving apparatus'is shown. And what was the primary P of Fig. 2 is now in reality the secondaryof an oscillation transformer which is inc uded in circuit with the variable capacity K a variable inductance or variometer V and a wave responsive device or detector W in shunt with which is connected a telephone receiver T orother suitable'instrumentality.

Here again' it will be understood that for receiving ondiflerent wave lengths the operator iieed merely turn the. hand wheel h to any of the positions, and then by varying V and K maximum response will be obtained by tuning. v In both transmitting and receiving apparatus above described, the total inductance of the primary circuit and the total inductance of the secondary circuit are simultaneously changed. for the different wave lengths by a single movement of the and for each of these different values of total inductance of primary circuit and of total inductance of secondary circuit, the optimum coupling is maintained without relative movement be tween the primary and secondary coils.

As well understood in this art,,the coefiicient of coupling between primary and secondary circuits is equal to the mutual induction divided by the squareroot of the product of the total inductance of the primary circuit multiplied by the total inductance of the secondary-circuit. By my invention, the co-etficient of coupling, or as the coupling, is maintained at the optimum value for the different wave lengths with a given separation between the primary and secondar coils for all those wave lengths. The switching apparatus changes the total inductances of primary and secondary circuits, the connections,

from the switch points to the primary, secondary and inductance being to such points in them that the mechanical coupling is maintained the same for the different wave lengths.

While with my apparatus hereinbefore described the change from one wave length orfrequency to another is accomplished by a, single movement, as

by a single actuation of the hand wheel h for 'a. given osition of the secondary S'wit h respect to t e primary P, or a given-separation between them, my invention coinprehends also the accomplisha plurality ment' of 't he same result for different relative positions of or separations between the secondary S and the primary P, both when such separation is changed by ,manually shifting one or the other and when such suitable motive device electrically or otherwise controlled from a distance to cause the shaft f to partake of the proper degrees of rotation for shifting the mechanism, to the proper; positions .for the various wave lengths or frequencies.

4 What I'claim is:

1. The combination with the primary and secondary of anoscillation transformer, of a variable inductance in circuit with one of them, a separate switch having connections with each of said primary, secondary and said inductance for varying them to simultaneously procure predetermined couplings between said primary and secondary and the requisite amount of inductance for each of of oscillation frequencies, and means common to all of'said actuating them in unison.

2. The combination with the primary and secondary windings of an oscillation trans- 'former, of an additional loading inductance in serieswith one of said windings, a switch switches for v for varying the magnitude of said inductance, a switch for varying a winding of said transformer, .and means causing said switches to move in unison with each other,

the variations caused by said switchesbeing complementary to each other for maintaining. a predetermined coupling for a plurality of different wave lengths.

3. Thecembination with a winding of an oscillation transformer, and a variable loading inductance in series therewith, of a unicontrol switch system connected with said winding and said loading inductance and serving to simultaneously complementarily vary the amount of each'in 'circuit for maintaining a predetermined coupling for each of a plurality of wave lengths,

4;. The combination with the primary and l secondary of an oscillation transformer occupying a predetermined position with respect to each other, in circuit with one of them,

cupying a predetermined position with reof a variable inductance and a separate switch having connections with each of said varying them simultaneously to maintain a predetermined coupling between primary and secondary circuits while adjusting the circuit of said inductance to different wave ity of switches for actuating them inunison.

6. The combination with the primary and secondary of an oscillation transformer,'of an inductance in circuit with one of them, a switch and connections therefrom to said primary for varying the amount of said primary in circuit,- a second switch and connections therefrom to said secondary for varying the amount of said secondary in circuit,

. a third switch and connections therefrom to said inductance for varying the amount of said inductance in circuit, means mechanically coupling together said switches, said connections being so adjusted that the circuits may be set to various wave lengths by movement of said means without changing the predetermined coupling between the cir cuits.-

7. The combination with a transformer, of adjusting means therefor, tuning means I in both primary and secondary circuits of said transformer, means common to said tuning means and tosaid adjusting means for operating them simultaneously tochange the wavelength of the circuits while maintaining them in tune with each other and maintaining o timum coupling. y

8. The com ination with a transformer, of adjusting means therefor, primary and secondary circuits therefor, a variable tuning inductance in series .with one of said cir cuits, a single. control means common to said adjusting means and to said inductance for ad usting the transformer and for varying the ma itude of the series tuning inductance s multaneously to vary the period of said one of said circuits while maintaining optimum cou ling between the two circuits.

' 9. The com ili'ation with a winding of an oscillation transformer, of an inductance incircuit therewith, said inductance having a plurality of sections, a switch connected with said winding and said inductance and serving to simultaneously complementarily alter the amount of each .m circuit for malntainmon to all of said means ing an o timum cou illing for each of a plurality 0 wave lengt s, and a variable connection to each section of inductance for varying the amount of such section to compensate for circuit variations.

10. The combination with an antenna, of a plurality of inductance sections, a variable connection to each section for varying the amount of such section to com ensate for lengths, and means common to said plural-i,

of said transformer in circuit, means for de-.

termining the portion of the other coil of said transformer in circuit, and means comfor actuatingthem in unison.

11. The combination with an antenna, of an oscillation transformer and an inductance, said. inductance having a plurality of separated sections, switchmg mechanism for simultaneously maintaining a predetermined coupling and adjusting for different wave lengt s, said switching mechanism having connections to variable connections on said inductance sections, said variable connections serving to compensate for antenna variations.

12. The combinationwith an antenna, of an oscillation transformer and an inducta'nce, said inductance having a plurality of separated sections, switching mechanism for simultaneously maintaining a redetermined coupling and adjusting for ifierent wave lengths, 'said switching mechanism havin connections to variable connections on sai inductance sections, said variable connections serving to compensate for antenna variations, the sections of said inductance" lying in parallel planes and so closely adjacent that they are within effective inductive influence of eachother.

13. In combination two operatively associated oscillatory circuits, a variable tuning element in each circuit, means other than said tuning elements for coupling said circuits, means to adjust the coupling, and commonoperating means for simultaneously varying said tuning elements to tune the circuits and adjusting said coupling means to optimum coupling for the selected wave length. Y

GEORGE H. CLARK. 

